<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div></div>
    <script>
       console.log(location.search); 
       var div = document.querySelector('div');
       //1.提取参数 location.search

       //2.去掉？  利用substr('起始的位置'，截取几个字符)
        var params = location.search.substr(1);//uname = 123
        console.log(params);
        
       //利用=号分割  键和值  split(' = ');

       var arr = params.split('=');
        div.innerHTML = arr[1];
    </script>
</body>
</html>